Cell culture is the process by which prokaryotic, eukaryotic or plant cells are grown under controlled conditions. Most recently the term "cell culture" has come to refer to the culturing of cells derived from multicellular eukaryotes, especially animal cells. The Cell Culture and Tumorigenecity Laboratory at the National Cancer Institute [unreadable] Frederick provides cell culture support for investigator-initiated research and development of xenograft (transplantation of living cells, tissues or organs from one species to another) mouse models;and maintains the metastatic cell line repository.